Surface treatment shape evaluation system and surface treatment shape

ABSTRACT

When the unevenness quantities of the surface of a surface-treated, existing concrete are measured at a given pitch by a measuring device  10 , the measured unevenness quantities are automatically collected by a CPU  21  to calculate the characteristic quantities of the surface-treated form of the existing concrete. The CPU  21  compares the calculated characteristic quantities with characteristic quantities beforehand stored in a data ROM  23  to give an evaluated result of the surface-treated form automatically. The evaluated result is displayed on a display device  40  or printed by a printer  50 , so that the result can be immediately checked. An ideal surface-treated form is a surface-treated form in which the average height of unevenness of the surface of the existing concrete is from 13 to 35% of the maximum particle size of aggregates contained in the existing concrete, and the slope length ratio thereof is 1.13 or more, and the unevenness having a height of 2 mm or more occupies 14% or more of all the unevenness.

FIELD OF THE INVENTION

The present invention relates to surface-treatment technique for anexisting concrete in an adhesion type overlay method adopted in therepair work of a concrete pavement, and in particular to asurface-treated form evaluating system and an ideal surface-treatedform.

BACKGROUND ART

In the repair work of a runway, a road or the like which is paved withconcrete, there has been adopted an adhesion type overlay method, inwhich the surface of an existing concrete is overlaid with a newconcrete. In the adhesion type overlay method, it is desirable that thenew concrete is jointed to the existing concrete with sufficientjointing strength.

Thus, in order to improve adhesive properties of a construction-jointedportion, an existing concrete has hitherto been subjected topretreatment for cutting the surface thereof before the overlay with anew concrete. The pretreatment is performed to remove an old surfacelayer and obtain an anchor effect, which is based on unevenness formedat the surface after the removal of the surface layer, on the newconcrete.

The cutting method may be, for example, a method of using a vibrationchipper to chip out the surface of a concrete.

However, the following technical problems remain in the cutting methodin the prior art.

The pretreatment using a chipper involves many works depending on humanhands. Therefore, the execution efficiency on a wide working spot islow. Moreover, workers are greatly effected by the generation of fineparticles and vibration. Additionally, it takes long time to removechipped concrete chips.

In order to improve adhesive properties of such a construction-jointedportion, for example, Japanese Patent Application Laid-Open No. 9-71902discloses an overlay method of jetting highly-pressured water on asurface layer of an existing concrete for a pavement by water jet toform a macro-unevenness surface, jetting a large number of small andhard balls, in spherical or other forms, composed of a metal such asiron onto the macro-unevenness surface by shot blast to form numerousmicro-unevenness having such an appropriate size that sufficientadhesion strength can be obtained, and overlaying the uneven surfacewhich has the macro-unevenness and the micro-unevenness with a concretematerial for a pavement, which has a given thickness, to form a surfacelayer on the uneven surface. According to this overlay method, theuneven surface can be easily and promptly formed without making pavementstrength weak by the combination of water jet with shot blast.Therefore, the whole of the period of construction can be shortened, andfurther the adhesion strength of the paved surface for overlay can beimproved still more than that in the case of using a chipper.

Even if the surface of an existing concrete is subjected to the surfacetreatment for forming unevenness by using both of water jet and shotblast, as disclosed in the above-mentioned publication, the adhesionstrength of the newly formed concrete to the surface layer of theexisting concrete varies according to the surface form generated basedon the degree of the treatment.

Thus, in order to obtain sufficient adhesion strength, it is desirableto overlay, on trial, existing concretes having surface forms which arelittle by little different with a new concrete, measure the adhesionstrength of the respective resultants by a tensile test or the like tospecify an ideal surface form, and evaluate whether or not such an idealsurface form is formed on an actual pavement construction spot on thebasis of the above-mentioned results.

However, in order to evaluate the surface-treated forms, it is necessaryto measure the quantity of the unevenness at the surfaces of theexisting concretes after the surface-treatment in their many points atthe pavement construction spot, calculate characteristic quantities suchas an average value of the unevenness quantities and a standarddeviation thereof from the collected results, and compare thecharacteristic quantities with the characteristic quantities of theabove-mentioned ideal surface-treated form. It takes a long time tocarry out such measurement, collection of data, calculation andcomparison on the spot and perform an exact evaluation. Thus, theshortening of the period of the construction may be hindered.

Thus, an object of the present invention is to provide a surface-treatedform evaluating system making it possible to evaluate a surface-treatedform of an existing concrete accurately for a short time in an adhesiontype overlay method of surface-treating the existing concrete and thenoverlaying the treated concrete with a new concrete; and an idealsurface-treated form of an existing concrete making it possible toobtain sufficient adhesion strength of a new concrete to the surface ofthe existing concrete.

DISCLOSURE OF THE INVENTION

To solve the above-mentioned problems, the invention according to claim1 is a system for evaluating a surface-treated form of an existingconcrete in an adhesion overlay method of forming macro-unevenness in asurface layer of the existing concrete with highly-pressured water,blasting hard balls onto the surface having the macro-unevenness by ashot blast treatment (a steel shot treatment or a steel grid treatment)to form micro-unevenness, and forming a surface layer which is composedof a pavement material of a new concrete and has a given thickness onthe uneven surface having the macro- and micro-unevenness, comprising:measuring means (such as a laser distance measuring meter or anultrasonic distance measuring meter) for measuring unevenness quantitiesof the surface of the existing concrete after the surface-treatments ata given pitch, characteristic quantity calculating means (such as CPU orMPU) for calculating characteristic quantities of the surface-treatedform of the existing concrete from collected results of the unevennessquantities measured by the measuring means, storing means (such as RAMor ROM) for storing characteristic quantities of a concrete having anideal surface-treated form which makes it possible to obtain sufficientadhesion strength of the new concrete to the surface of the existingconcrete, and evaluating means (such as CPU or MPU) for comparing thecharacteristic quantities calculated by the characteristic quantitycalculating means with those stored in the storing means and thenoutputting a result obtained by the comparison.

When in the above-mentioned surface-treated form evaluating systemaccording to a first aspect of the present invention the unevennessquantities of the surface of the existing concrete after thesurface-treatment are measured at the given pitch by the measuringmeans, the measured unevenness quantities are automatically collected bythe characteristic quantity calculating means to calculate thecharacteristic quantities of the surface-treated form of the existingconcrete. The characteristic quantities calculated by the characteristicquantity calculating means are compared with the characteristicquantities beforehand stored in the storing means by the evaluatingmeans to obtain an evaluated result of the surface-treated formautomatically. This evaluated result is displayed on the display meanssuch as a CRT or LCD, or printed by printing means. Thus, thesurface-treated form of the existing concrete can be accuratelyevaluated for a short time.

According to a second aspect of the invention, as the characteristicquantities in the surface-treated form evaluating system according tothe first aspect, there is used at least one of the average of theunevenness quantities and the standard deviation thereof. In this way,accurate evaluation can be made on the basis of the objective measureddata.

According to a third aspect of the invention, attention is paid to thefact that the characteristic quantities are different in accordance withthe particle sizes of aggregates contained in the existing concrete. Thestructure of surface-treated form evaluating system according to thefirst and second aspects further comprises average inputting means forinputting the average of particle sizes of aggregates contained in theexisting concrete. In the structure, such data that the average of theparticle sizes and the characteristic quantities correspond to eachother are stored in the storing means, and the evaluating means comparesthe characteristic quantities calculated by the characteristic quantitycalculating means with the characteristic quantities stored in thestoring means, correspondingly to the average of the particle sizes, toevaluate the surface-treated form. In this way, more accurate evaluationcan be made.

According to a fourth aspect of the invention, in the surface-treatedform evaluating system according to any one of the first to thirdaspects, the ideal surface-treated form is a surface-treated form inwhich an average height (depth)of the unevenness is from 13 to 35% (morepreferably 13 to 32.5%) of the maximum particle size of the aggregatescontained in the existing concrete.

According to a fifth aspect of the invention, in the surface-treatedform evaluating system according to any one of the first to fourthaspects, the ideal surface-treated form is specified. That is, the idealsurface-treated form is a surface-treated form in which a slope lengthratio of the surface of the existing concrete is 1.13 or more. The slopelength ratio is a ratio of the distance (measured length) along theunevenness of the measured surface to the straight distance (measureddistance) from the start point of the measurement to the end pointthereof. For example, in the case that the length along the unevennessof the measured surface in the range of a straight distance of 50 cm is68 cm, the slope length ratio of the measured surface in this range is1.36.

According to a sixth aspect of the invention, in the surface-treatedform evaluating system according to any one of the first to fifthaspects, the ideal surface-treated form is specified. That is, the idealsurface-treated form is a surface-treated form in which 14% or moreamong all the unevenness of the surface of the existing concrete isunevenness having a height of 2 mm or more.

According to a seventh aspect of the invention, in the adhesion typeoverlay method, in which the existing concrete is subjected to asurface-treatment and then the treated surface is overlaid with a newconcrete, the ideal surface-treated form of the existing concrete isspecified. That is, the average height (depth) of unevenness of thesurface of the existing concrete is from 13 to 35% (more preferably 13to 32.5%) of the maximum particle size of aggregates contained in theexisting concrete, and the slope length ratio thereof is 1.13 or more,and the unevenness having a height of 2 mm or more occupies 14% or moreof all the unevenness. Such a surface-treated form makes it possible togain certainly sufficient adhesion strength of the new concrete to theexisting concrete surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating an outline of working steps of a repairconstruction of a concrete pavement according to an adhesion typeoverlay method.

FIGS. 2(a) to 2(c) are view illustrating states of an existing concretesurface worked in the respective steps shown in FIG. 1.

FIG. 3 is a side view, partly in section, which illustrates a mechanismof a grinding and sweeping machine used in the shot blast treatmentillustrated in FIG. 1.

FIG. 4 is an outline view of a surface-treated form evaluating systemaccording to an embodiment of the present invention.

FIG. 5 is a view for explaining the measuring method by a measuringdevice illustrated in FIG. 4.

FIG. 6 is a view showing an example of surface-treated forms obtained bythe measurement.

FIG. 7 is a cross section of a structure of a tensile test device.

FIG. 8 is a graph showing the relationship between the average depthobtained by arithmetically averaging the depths from tips ofsurface-treated convex portions to bottoms of concave portions andadhesion strength.

FIG. 9 is a graph of an example of frequency distribution of unevennessheights of a surface treated by a specific method.

FIG. 10 is a graph of an example of frequency distribution of unevennessheights of a surface treated by a specific method.

FIG. 11 is a graph of an example of frequency distribution of unevennessheights of a surface treated by a specific method.

FIG. 12 is a graph of an example of frequency distribution of unevennessheights of a surface treated by a specific method.

FIG. 13 is a graph of an example of frequency distribution of unevennessheights of a surface treated by a specific method.

FIG. 14 is a graph of an example of frequency distribution of unevennessheights of a surface treated by a specific method.

FIG. 15 is a graph showing the relationship between the average ofunevenness quantities according to the respective methods and tensilestrength.

FIG. 16 is a graph showing the relationship between the standarddeviation of unevenness quantities according to the respective methodsand tensile strength.

FIG. 17 is a graph showing the relationship between the average slopelength of the unevenness according to the respective methods and tensilestrength.

FIG. 18 is a graph showing the relationship between the averageunevenness length according to the respective methods and tensilestrength.

FIG. 19 is a graph showing the relationship between the slope lengthratio of the unevenness according to the respective methods and tensilestrength.

FIG. 20 is a graph showing the relationship between the ratio ofunevenness having a height of less than 2 mm at the surfaces of existingconcretes treated by the respective methods and tensile strength.

FIG. 21 is a graph showing accumulated frequency distributions, based onthe respective methods, of the heights of unevenness in the case that atensile strength of 20 kgf/cm² or more can be obtained in a tensilestrength test.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the attached drawings, embodiments of the present inventionwill be described hereinafter.

The adhesion type overlay method will be first described.

FIG. 1 is a view illustrating an outline of working steps of a repairconstruction of a concrete pavement according to the adhesion typeoverlay method. FIGS. 2(a) to 2(c) illustrate states of an existingconcrete surface worked in the respective steps.

As shown in FIG. 1, in the repair construction according to the adhesiontype overlay method, water jet treatment is performed as a firstsurface-treatment.

In the water jet treatment, highly pressured water is jetted from awater jet nozzle of a water jet vehicle 3 pulled by a water tank vehicleand a power unit 2 toward a surface 1 of an existing concrete, so as toform a macro-unevenness surface. At this time, the jet nozzle is notfixed and traverses the direction along which the body of the vehicleadvances. In this way, the unevenness is formed over the whole of thewidth direction of the vehicle. A vacuum vehicle 4 follows the water jetvehicle 3 to absorb and remove jetted water and scraps. FIG. 2(a) showsthe state of macro-unevenness 1 a obtained in this step.

The water jet treatment is treatment for cutting a working surface byjetting highly pressured water, and has been conventionally used, as acutting technique without giving a bad influence on the cut surface, inwide fields. In general, the water jet treatment is used exclusively forcutting it. In the present invention, however, the cutting treatment isperformed with movement, so as to obtain an unevenness-treated surfacehaving a given cut depth and a given pitch.

Next, as a second surface-treatment, a shot blast treatment is performedto form a finer unevenness surface (micro-unevenness 1 b). This is atreatment in which hard balls such as steel balls having a smalldiameter are blasted onto a treatment surface from a power unit vehicle6 connected to the front of a tractor 5 to form unevenness. In the samemanner as above, continues blast action is performed while the blastaction traverses the wide direction of the vehicle.

Fine particles generated by this treatment and the steel balls areabsorbed by the tractor 5, and the steel balls are collected.

The shot blast treatment is a conception including steel shot treatmentand steel grid treatment. The steel shot treatment is treatment forforming micro-unevenness at the surface of an existing concrete bydischarging iron balls in a spherical form (for example, steels ballshaving a diameter of 0.4 to 2.4 mm) thereon at a high speed by means ofa machine (grinding and sweeping machine) as illustrated in FIG. 3.These balls are discharged at a speed of 70 to 90 m/second by therotation of an impeller driven by a motor for the impeller illustratedin FIG. 3. This density of the threw balls is adjusted according to thehardness of aggregates of the existing concrete. The density can beselected within a wide range from, for example, 50 to 1000 kg/cm² inaccordance with situations. The steel balls after the discharging,together with fine particles generated by grinding and sweeping, arecollected by a vacuum machine. The steel balls that can be reused areseparated and repeatedly used.

The steel grid treatment is treatment using iron balls in anon-spherical form instead of the spherical iron balls used in the steelshot treatment. Other ways of the treatment are the same as those of thesteel shot treatment.

The non-spherical form means all forms other than a spherical form. Thehard balls include balls, in a spherical or non-spherical form, composedof iron, other metals or hard materials besides metals.

By using both of the water jet treatment and the shot blast treatment,the surface 1 of the existing concrete can be made up to asurface-treated form having a desired unevenness surface (unevennesssurface having macro- and micro-unevenness). These treatments can bemade automatic by using a heavy working vehicle.

FIG. 2(b) illustrates the state that the micro-unevenness 1 b is formedat the surface having the macro-unevenness 1 a.

Next, the overlay surface having the macro-unevenness 1 a is overlaidwith a new concrete. This work is performed by strewing the new concretefrom a concrete mixer vehicle 7 following the tractor 5. The roadsurface is made flat by placing and spreading treatment using a rollingcompaction working vehicle 8 following this vehicle 7 (see FIG. 2(c)).

Subsequently, the concrete is cured and hardened to finish the overlaywork.

In the repair work of the concrete pavement according to the adhesiontype overlay method, as performed as above, it is necessary to evaluatewhether or not the existing concrete surface 1 is an idealsurface-treated form, that is, a surface-treated form which makes itpossible to obtain a sufficient anchor effect on the new concrete by theunevenness formed at the existing concrete surface 1 when the existingconcrete is overlaid with the new concrete.

The present invention provides a surface-treated form evaluating systemand an evaluating process which makes it possible to evaluate thesurface-treated form of the existing concrete surface 1 on the spot ofthe repair construction of a concrete pavement according to the adhesiontype overlay method.

The following will describe the surface-treated form evaluating systemaccording to the present invention.

FIG. 4 is an outline view of a surface-treated form evaluating systemaccording to an embodiment of the present invention, and illustrates asystem comprising a measuring device 10 for measuring, at a given pitch,the unevenness quantities of the existing concrete surface 1 after thesurface-treatment; an evaluating device 20 for evaluating thesurface-treated form on the basis of the measured values by themeasuring device 10; an operation unit 30 for inputting operationindications and various values into the evaluating device 20; a displaydevice 40 for displaying various data outputted from the evaluatingdevice 20 on a CRT screen or the like; and a printer 50 for printing thevarious data if necessary.

The measuring device 10 has a laser displacement meter 11 for measuringthe unevenness quantities of the existing concrete surface 1 withsuper-high accuracy, and a non-illustrated moving mechanism for holdingthis laser displacement meter 11 and moving it at a constant speed inthe horizontal direction (XY direction in FIG. 4). The laserdisplacement meter 11 has a laser oscillator (LD) 12 for emitting alaser beam toward the existing concrete surface 1 at very shortintervals of pulses, and a light receiving element (PD) 13 for detectinga reflective laser beam from the existing concrete surface 1, in orderto measure the unevenness quantity on the basis of the period from theemission of the laser beam to the return thereof. In the measuringdevice 10, the laser displacement meter 11 is moved in the X and Ydirections by the moving mechanism while the meter 11 is operated. Inthis way, as shown in FIG. 5, the meter 11 scans a measuring range Rhaving a given area Lx×Ly (for example, Lx×Ly=50 cm×50 cm), in a matrixform, at given pitches px and py (for example, px=2 mm and py=2 mm) totake measurements. The measured data are successively transmitted to themeasuring device 10.

The evaluating device 20 has a CPU 21, a program ROM 22 in which controlprograms to be executed by the CPU 21 are stored, a data ROM 23 in whichcharacteristic quantities of an ideal surface-treated form which havebeen beforehand obtained from tests and measurements, that is, data onthe average of the unevenness quantities and data on the standarddeviation thereof, a RAM 24 which is used as a working area when the CPU21 executes various processings, and interfaces (I/F) 25-28 forinterconnecting this evaluating device 20 to external devices.

In the data ROM 23, the following are stored: characteristic quantities(that is, data on the average of the unevenness quantities and data onthe standard deviation thereof) of ideal surface-treated forms obtainedwhen the adhesion strength between an existing concrete and a newconcrete is measured with a change in the average of the particle sizesof aggregates contained in the existing concrete (which will be referredto as an average particle size hereinafter). These are storedcorrespondingly to the respective average particle sizes of therespective aggregates.

The CPU 21 controls the whole of the surface-treatment form evaluatingsystem in accordance with indications through the operation unit 30, andcollects measured data on the whole of the measuring range R, which aresuccessively forwarded from the measuring device 10, to calculate thecharacteristic quantities, within the measured range R, of thesurface-treated form of the existing concrete surface 1, that is, theaverage of the unevenness quantities and standard deviation thereof andthen store them in given memory areas of the RAM 24. When the averageparticle size of the aggregates contained in the existing concrete,which is an object of evaluation, is inputted through the operation unit30 to indicate the execution of evaluation, the average of theunevenness quantities and the standard deviation thereof, as idealvalues, corresponding to the inputted average particle size are read outfrom the data ROM 23 so as to compare them with the average of theunevenness quantities, as the measured values, and the standarddeviation which are stored in the RAM 24. The difference between theideal values and the measured values is displayed as evaluation resultson the display device 40. The display content on the display device 40can be changed by the indication through operation unit 30. Thus, it ispossible to display the evaluated results and the various collecteddata, display the unevenness quantities of the respective measuringpoints, display a graph of the frequency distribution of the unevennessquantities, as shown in, for example, FIGS. 9 to 14, or display the datastored in the data ROM 23 in a table. If necessary, the evaluatedresults, the various collected results, and the like can be printed onpaper with the printer 50 and kept.

As described above, in the surface-treated form evaluating system ofthis embodiment, it is possible to perform successively the collectionof the measured values, the calculation of the characteristic quantitiesof the surface-treated forms, and the comparison of the calculatedcharacteristic quantities with the characteristic quantities of theideal surface-treated forms which have been beforehand obtained in theevaluating device 20 only by setting the measuring device 10 on theexisting concrete surface 1, the surface-treated form of which should beevaluated, and then measuring the unevenness quantities thereof. Theevaluated results thereof can be displayed on the display device 40. Itis therefore possible to evaluate the surface-treated form of theexisting concrete accurately for a short time on the repair constructionspot.

In the above-mentioned embodiment, the following is displayed as anevaluated result: the difference between the average of the unevennessquantities of the existing concrete surface, which is an object forevaluation, and the standard deviation thereof and the characteristicquantities of the ideal surface-treated forms which have been beforehandobtained. The present invention is not however to this example. Forexample, when about such averages and standard deviations the differencebetween the ideal values thereof and the measured values thereof isbelow an allowable value which has been beforehand set, the followingfact may be displayed: the existing concrete surface has an idealsurface-treated form.

If there are stored in the data ROM 23 not only the data correspondingto the average particle size of the aggregates of the existing concretebut also other detailed data based on different conditions,corresponding to other materials such as mortar of the existingconcrete, a material of a new concrete pavement, and the like andfurther an ideal value corresponding to the detailed condition specifiedthrough the operation unit 30 is used, more accurate evaluation can beperformed.

In the case that the average particle size of aggregates does not changevery much in accordance with any object to be evaluated, it is notnecessary to store in the data ROM 23 the data on the average of theunevenness quantities and the data on the standard deviation thereof inthe state that they are caused to correspond to the average particlesize of the aggregates.

In the system shown in FIG. 4, the evaluating device 20, the operationunit 30 and the display device 40 are separately composed, but all otherunits than the measuring device 10 may be integrated with the evaluatingdevice 20. An operation panel having the functions of both of theoperation unit 30 and the display device 40 may be fitted to theevaluating device 20.

It is not necessary to have both of the display device 40 and theprinter 50 as means for outputting evaluated results. The system of thepresent invention may have only either one of them.

The system of the present invention may have data storing means forcausing measured data, collected data, evaluated results and the like tobe stored in a recording medium such as a floppy disc or an opticaldisc, as well as the above-mentioned units or devices. If the datacollected on the spot can be stored in the floppy disc or the like, themeasured data can be brought back to a laboratory and analyzed or causedto function as a data base. Therefore, the measured data can be used asreference data for a subsequent research or construction.

As the evaluating device 20 a personal computer may be used and as theoperation unit 30 a keyboard attached to this may be used. In this case,if a small and light computer such as a notebook size personal computeris used as the evaluating device 20, it can easily be carried on theconstruction spot. Thus, evaluating work can be effectively performed.The communication function of the personal computer may be used totransmit data collected on the construction spot to a laboratory or thelike.

EXAMPLES

The following will describe the surface-treated form evaluating systemby way of Example.

[Grasp of a Surface-treated Form]

Tensile stress and shear stress simultaneously act the interface betweennew and old concretes. In order that the new concrete is not exfoliated,it is important to have sufficient strength against these stresses.

Thus, in order to grasp the surface-treated form making it possible toobtain sufficient strength at the interface, paying attention to tensilestrength, the inventors prepared plural surface-treated forms bysubjecting the surfaces of an existing concrete to differentsurface-treatment methods, and carried out tensile tests on the spot.

As the surface-treatment methods, there was adopted any one or acombination of a water jet treatment, a shot blast treatment and acutting treatment with a chipper. Details thereof are shown in Table 1.Three areas (50 cm×50 cm) in the existing concrete surface weresubjected to each of the surface-treatment methods. Before each of theareas was overlaid with a sample for tensile tests, the unevennessquantity of the existing concrete surface after the surface-treatmentwas measured with a measuring device using a laser displacement meter.An example of surface-treated forms obtained by the measurement is shownin FIG. 6. The pitch of the measurement was 0.2 mm, and the length ofthe measurement was 50 cm. Twenty measuring lines in total weremeasured.

TABLE 1 Sorts of surface-treatment methods, and results of themeasurement of average depth Average Method depth No. Method (mm) A-1WJ1700 kgf/cm², Nozzle angle: 22°, Traverse speed: 6.71 30 cm/sec. A-2WJ1900 kgf/cm², Nozzle angle: 22°, Traverse speed: 10.16 30 cm/sec. A-3WJ1050 kgf/cm², One nozzle, Speed: 0.14 m/min. 13.66 B-1 Steel shotTSH170 250 kg/m² 2.33 B-2 Steel shot TSH170 750 kg/m² 3.99 B-3 Steelshot TSH170 1500 kg/m² 4.92 C-1 Steel grid TGE200 250 kg/m² 1.81 C-2Steel grid TGE200 750 kg/m² 2.87 C-3 Steel grid TGE200 1500 kg/m² 3.89D-1 Cutting + WJ1700 kgf/cm², Nozzle angle: 22°, Tra- 10.27 verse speed:30 cm/sec. D-2 Cutting + WJ1900 kgf/cm², Nozzle angle: 22°, Tra- 11.34verse speed: 30 cm/sec. D-3 Cutting + WJ1050 kgf/cm², One nozzle, Speed:0.14 14.49 m/min. D-4 Cutting + WJ 900 kgf/cm², Rotating nozzle Speed:11.36 0.16 m/min. E-1 Cutting + Steel shot TSH170 250 kg/m² 3.80 E-2Cutting + Steel shot TSH170 750 kg/m² 3.92 E-3 Cutting + Steel shotTSHI70 1500 kg/m² 5.73 E-4 Cutting + Steel grid TGE200 750 kg/m² 4.89F-1 WJ1700 kgf/cm², Nozzle angle: 22° + Steel shot 7.51 TSH170 100kg/m², Traverse speed: 30 cm/sec. (6.30) F-2 WJ1900 kgf/cm², Nozzleangle: 22° + Steel shot 10.77 TSH170 100 kg/m², Traverse speed: 30cm/sec. (10.05) F-3 WJ1050 kgf/cm², 0.14 m/min One nozzle + Steel shot13.16 TSH170 100 kg/m² (14.00) F-4 WJ1900 kgf/cm², Nozzle angle: 22° +Steel grid 8.82 TGE200 100 kg/m², Traverse speed: 30 cm/sec. (8.63)Notes: The values inside parentheses are measured values before shot orgrid was received.

[Tensile Test Method and Used Materials]

FIG. 7 shows a structure of a tensile test device. This tensile testdevice 60 is substantially composed of a self-support load-putting frame61 set on an existing concrete surface 1, which is an object to bemeasured, a center hole jack 62 fixed on the load-putting frame 61, aload cell 63 for driving the center hole jack 62, and a PC steel rod 64which can be held by the center hole jack 62 and moved upwards anddownwards. A sample 65 in which the lower portion of the PC steel rod 64was embedded was formed on a treatment surface 1 a of an existingconcrete surface 1, and subsequently the PC steel rod 64 was strainedwith the center hole jack 62.

The tensile test device 60 was used to perform a tensile test of thesample 65 having a cylindrical shape with a diameter of 20 cm and aheight of 60 cm. A concrete used in the test was a normal Portlandcement having a ratio of water to cement of 39%, a slump of 6 to 7 cm, adesigned bending strength of 50 kgf/cm², and a maximum particle size ofcoarse aggregates of 40 mm. The treatment surface 1 a was cleaned with awire brush before overlay with the concrete. This was repeated. Thus, 6samples 65 were made on treatment surfaces 1 a and then they weresubjected to tensile tests.

[Tensile Test Results and Consideration]

FIG. 8 is a graph showing the relationship between the average depthobtained by arithmetically averaging the depths from tips ofsurface-treated convex portions to bottoms of concave portions andadhesion strength. It can be understood from this graph that thesurface-treated forms having an appropriate depth make it possible toobtain high adhesion strength and the method using water jet treatmentis very effective.

It can also be understood that in order to obtain an adhesion strengthof 20 kgf/cm² or more, which is a sufficient adhesion strength, in thecase that the maximum particle size of coarse aggregates is 40 mm, theaverage depth of the unevenness needs to be within the range of about5.2 mm to 13.0 mm. If this range is converted to a range of percentagesto the maximum particle size of the coarse aggregates, the range is from13% to 32.5% (corresponding to the fourth and seventh aspects).

FIGS. 9 to 14 show the frequency distribution of the unevenness heightaccording to the respective methods. These are results measured with ameasuring device using the above-mentioned laser displacement meter.Concerning all surface-treated forms, the treated surface whose heightsof the unevenness was somewhat broadly distributed so that the skirt ofthe shape of the distribution was spread was compared with the treatedsurface whose heights thereof was unevenly distributed around 0 mm, inwhich the difference between the heights of convex and concave portionswas small. As a result, the former had higher adhesion strength.According to all the method using water jet, distribution shapes of theformer were obtained. It can be understood from this result that themethod in which the surface after water jet treatment is subjected toshot blast treatment is preferable and in particular the F4 method ismost preferable for the surface-treating method adopted in the adhesiontype overlay method.

FIG. 15 is a graph showing the relationship between the average ofunevenness quantities according to the respective methods and tensilestrength. FIG. 16 is a graph showing the relationship between thestandard deviation of unevenness quantities according to the respectivemethods and tensile strength. FIG. 17 is a graph showing therelationship between the average slope length of the unevennessaccording to the respective methods and tensile strength. FIG. 18 is agraph showing the relationship between average unevenness lengthaccording to the respective methods and tensile strength. These aregraphs in which measured values by means of the measuring device usingthe above-mentioned laser displacement meter were collected for therespective methods and these values were plotted. The average of theunevenness quantities is defined as follows. Higher values than apredetermined standard point (the unevenness quantity=0) are measured aspositive values and lower values than the standard point are measured asnegative values, and such measured values are obtained for the whole ofthe treatment surface 1. The average of the obtained values is theaverage of the unevenness quantities. The average slope length is avalue obtained by calculating the length from the tip of a convexportion to the bottom of a concave portion, along its surface, over allof the treatment surface 1 a and then averaging the obtained values. Theaverage unevenness is a value obtained by calculating the depth from thetip of a convex portion to the bottom of a concave portion over all ofthe treatment surface 1 a and then averaging the obtained values.

It can be understood from all of the above-mentioned relationships thatthe method in which the surface after water jet treatment is subjectedto shot blast treatment is preferable as a surface-treating methodadopted for the adhesion type overlay method. In particular, the F4method is most preferable.

FIG. 19 is a graph showing the relationship between the slope lengthratio of the unevenness according to the respective methods and tensilestrength. It can be understood from the measured results that in orderto obtain a sufficient adhesion strength of 20 kgf/cm² or more the slopelength ratio should be 1.13 or more (corresponding to the fifth aspect).

FIG. 20 is a graph showing the relationship between the ratio ofunevenness having a height of less than 2 mm at the surface of theexisting concrete treated by the respective methods and tensilestrength. FIG. 21 is a graph showing accumulated frequencydistributions, based on the respective methods, of the heights ofunevenness in the case that a tensile strength of 20 kgf/cm² or more canbe obtained in a tensile strength test. It can be understood from thesemeasured results that, in order to obtain a sufficient adhesion strengthof 20 kgf/cm² or more, 14% or more among all the unevenness of the wholeof the treated-surface is unevenness having a height of 2 mm or more(corresponding to the sixth and seventh aspects).

Thus, in the present invention, existing concretes havingsurface-treated forms which are little by little different on trial areoverlaid with a new concrete (sample) and then the adhesion strengths ofthe respective resultants are measured to specify an idealsurface-treated form. As the characteristic quantities of thesurface-treated form, the average of the unevenness quantities, thestandard deviation thereof and the average slope length and the slopelength ratio are calculated, and then the calculated results arebeforehand stored as ideal values in the data ROM of the evaluatingdevice. The ideal values stored in the data ROM are compared withmeasured values on the construction spot to evaluate the surface-treatedform of the existing concrete surface on the contraction spot.

Therefore, sufficient adhesion strength of the new concrete to theexisting concrete can be obtained by treating the existing concretesurface in the manner that the ideal values stored in the data ROMbecome equal to or similar to the measured values on the constructionspot, and then overlaying the existing concrete surface with the newconcrete.

As described above, the present invention exhibits the followingexcellent advantages.

In the surface-treated form evaluating system according to the firstaspect, the characteristic quantities of the surface-treated form of theexisting concrete are calculated from the unevenness quantities measuredby the measuring means. A result of the surface-treated form of theexisting concrete can be automatically obtained for a short time on thebasis of the characteristic quantities and the characteristic quantitiesbeforehand stored in the storing means. This evaluated result isdisplayed on the display means such as a CRT or and LCD, or printed byprinting means. Thus, the surface-treated form of the existing concretecan be accurately evaluated for a short time.

According to the surface-treated form evaluating system of the secondaspect, in the system according to the first aspect, as thecharacteristic quantities there is used at least one of the average ofthe unevenness quantities and the standard deviation thereof. In thisway, accurate evaluation can be made on the basis of the objectivemeasured data.

According to the surface-treated form evaluating system of the thirdaspect, in the system according to first or second aspect, such datathat the average of the particle sizes and the characteristic quantitiescorrespond to each other are stored in the storing means, and thecalculated characteristic quantities are compared with theabove-mentioned stored characteristic quantities, correspondingly to theaverage of the particle sizes, to evaluate the surface-treated form. Inthis way, more accurate evaluation can be made.

According to the fourth aspect of the invention, in the system accordingto any of the first to third aspects, the ideal surface-treated form isa surface-treated form in which an average height of the unevenness isfrom 13 to 35% of the maximum particle size of the aggregates containedin the existing concrete. Evaluation using this makes it possible toobtain a more objective result.

According to the fifth aspect of the invention, in the surface-treatedform evaluating system according to any of the first to fourth aspects,the ideal surface-treated form is a surface-treated form in which aslope length ratio of the surface of the existing concrete is 1.13 ormore. Evaluation using this makes it possible to obtain a more objectiveresult.

According to the sixth aspect of the invention, in the system accordingto any of the first to fifth aspects, the ideal surface-treated form isa surface-treated form in which 14% or more among all the unevenness ofthe surface of the existing concrete is unevenness having a height of 2mm or more. Evaluation using this makes it possible to obtain a moreobjective result.

According to the seventh aspect of the invention, the following idealsurface-treated form is adopted. That is, the average height (depth) ofunevenness of the surface of the existing concrete is from 13 to 35% ofthe maximum particle size of aggregates contained in the existingconcrete, and the slope length ratio thereof is 1.13 or more, and theunevenness having a height of 2 mm or more occupies 14% or more of allthe unevenness. Adoption of such a surface-treated form makes itpossible to gain certainly sufficient adhesion strength of the newconcrete to the existing concrete surface.

What is claimed is:
 1. A system for evaluating a surface-treated form ofan existing concrete in an adhesion overlay method of formingmacro-unevenness in a surface layer of the existing concrete withhighly-pressured water, blasting hard balls onto the surface having themacro-unevenness by a shot blast treatment to form micro-unevenness, andforming a surface layer which is composed of a pavement material of anew concrete and has a given thickness on the uneven surface having themacro- and micro-unevenness, comprising: measuring means for measuringunevenness quantities of the surface of the existing concrete after thesurface-treatments at a given pitch, characteristic quantity calculatingmeans for calculating characteristic quantities of the surface-treatedform of the existing concrete from collected results of the unevennessquantities measured by the measuring means, storing means for storingcharacteristic quantities of a concrete having an ideal surface-treatedform which makes it possible to obtain sufficient adhesion strength ofthe new concrete to the surface of the existing concrete, and evaluatingmeans for comparing the characteristic quantities calculated by thecharacteristic quantity calculating means with those stored in thestoring means and then outputting a result obtained by the comparison.2. A surface-treated form evaluating system according to claim 1,wherein the characteristic quantities include at least one of theaverage of the unevenness quantities and the standard deviation thereof.3. A surface-treated form evaluating system according to claim 2, whichfurther comprises average inputting means for inputting the average ofparticle sizes of aggregates contained in the existing concrete, suchdata that the average of the particle sizes and the characteristicquantities correspond to each other being stored in the storing means,and the evaluating means comparing the characteristic quantitiescalculated by the characteristic quantity calculating means with thecharacteristic quantities stored in the storing means, correspondinglyto the average of the particle sizes, to output a result obtained by thecomparison.
 4. A surface-treated form evaluating system according toclaim 3, wherein the ideal surface-treated form is a surface-treatedform in which a slope length ratio of the surface of the existingconcrete is 1.13 or more.
 5. A surface-treated form evaluating systemaccording to claim 3, wherein the ideal surface-treated form is asurface-treated form in which 14% or more among all the unevenness ofthe surface of the existing concrete is unevenness having a height of 2mm or more.
 6. A surface-treated form evaluating system according toclaim 3 wherein the ideal surface-treated form is a surface-treated formin which an average height of the unevenness is from 13 to 35% of themaximum particle size of the aggregates contained in the existingconcrete.
 7. A surface-treated form evaluating system according to claim6, wherein the ideal surface-treated form is a surface-treated form inwhich a slope length ratio of the surface of the existing concrete is1.13 or more.
 8. A surface-treated form evaluating system according toclaim 7, wherein the ideal surface-treated form is a surface-treatedform in which 14% or more among all the unevenness of the surface of theexisting concrete is unevenness having a height of 2 mm or more.
 9. Asurface-treated form evaluating system according to claim 2 wherein theideal surface-treated form is a surface-treated form in which an averageheight of the unevenness is from 13 to 35% of the maximum particle sizeof the aggregates contained in the existing concrete.
 10. Asurface-treated form evaluating system according to claim 2, wherein theideal surface-treated form is a surface-treated form in which a slopelength ratio of the surface of the existing concrete is 1.13 or more.11. A surface-treated form evaluating system according to claim 2,wherein the ideal surface-treated form is a surface-treated form inwhich 14% or more among all the unevenness of the surface of theexisting concrete is unevenness having a height of 2 mm or more.
 12. Asurface-treated form evaluating system according to claim 1, whichfurther comprises average inputting means for inputting the average ofparticle sizes of aggregates contained in the existing concrete, suchdata that the average of the particle sizes and the characteristicquantities correspond to each other being stored in the storing means,and the evaluating means comparing the characteristic quantitiescalculated by the characteristic quantity calculating means with thecharacteristic quantities stored in the storing means, correspondinglyto the average of the particle sizes, to output a result obtained by thecomparison.
 13. A surface-treated form evaluating system according toclaim 12 wherein the ideal surface-treated form is a surface-treatedform in which an average height of the unevenness is from 13 to 35% ofthe maximum particle size of the aggregates contained in the existingconcrete.
 14. A surface-treated form evaluating system according toclaim 12, wherein the ideal surface-treated form is a surface-treatedform in which a slope length ratio of the surface of the existingconcrete is 1.13 or more.
 15. A surface-treated form evaluating systemaccording to claim 12, wherein the ideal surface-treated form is asurface-treated form in which a slope length ratio of the surface of theexisting concrete is 1.13 or more.
 16. A surface-treated form evaluatingsystem according to claim 12, wherein the ideal surface-treated form isa surface-treated form in which 14% or more among all the unevenness ofthe surface of the existing concrete is unevenness having a height of 2mm or more.
 17. A surface-treated form evaluating system according toclaim 1, wherein the ideal surface-treated form is a surface-treatedform in which an average height of the unevenness is from 13 to 35% ofthe maximum particle size of the aggregates contained in the existingconcrete.
 18. A surface-treated form evaluating system according toclaim 1, wherein the ideal surface-treated form is a surface-treatedform in which a slope length ratio of the surface of the existingconcrete is 1.13 or more.
 19. A surface-treated form evaluating systemaccording to claim 1, wherein the ideal surface-treated form is asurface-treated form in which 14% or more among all the unevenness ofthe surface of the existing concrete is unevenness having a height of 2mm or more.
 20. A surface-treated form of an existing concrete in anadhesion type overlay method, in which the existing concrete issubjected to a surface-treatment and then the treated surface isoverlaid with a new concrete, wherein the average height of unevennessof the surface of the existing concrete is from 13 to 35% of the maximumparticle size of aggregates contained in the existing concrete, and theslope length ratio thereof is 1.13 or more, and the unevenness having aheight of 2 mm or more occupies 14% or more of all the unevenness.